1. Field of the Invention
The present invention relates to a diagnostic parameter calculation method and a system for diagnosis and a diagnostic program, and more particularly, to a diagnostic parameter calculation method, a system for diagnosis and a diagnostic program suitable for diagnosing symptoms of patients through electrocardiogram analysis.
2. Description of the Related Art
Many technologies for diagnosing symptoms of patients by analyzing an electrocardiogram are developed and examples of these technologies include technologies that allow correct diagnosis by accurately and automatically recognizing characteristic points of individual electrocardiogram waveforms (Japanese Patent Laid-Open No. 8-56914, Japanese Patent Laid-Open No. 9-201344, etc.), technologies that make a diagnosis by analyzing individual electrocardiogram waveforms (Japanese Patent Laid-Open No. 10-225443, U.S. Pat. No. 5,609,158, U.S. Pat. No. 5,560,368, etc), and technologies that extract time-series data such as R-R interval from electrocardiogram waveform and make a diagnosis by analyzing the time-series data (U.S. Pat. No. 5,755,671, Japanese Patent Laid-Open No. 6-54815, etc), etc. Using these technologies allows more efficient and more speedy diagnosis than diagnosis depending only on a visual check of electrocardiogram and reduces a possibility of overlooking symptoms.
The above-described conventional technologies carry out an observation and analysis of electrocardiogram waveforms for a few minutes or over 10 minutes at longest, but it is often the case that data suggesting some abnormality of the heart is not obtained in such a short
period. For example, if myocardial infarction occurs, there is a danger of sudden death in a few hours due to ventricular tachycardia and the probability that arrhythmia will occur in a few days after the occurrence of myocardial infarction reaches 90%. The rate of occurrence of arrhythmia then reduces, but 5 to 10% of patients die within one year. Therefore it is desirable to acquire and monitor electrocardiogram data for many hours continually for diagnosis of such patients. However, according to the prior arts, a doctor reads the record by the naked eye and makes diagnosis after the recording is finished, or a doctor extracts short time data that he/she regards as abnormal from the recorded data and subjects the data to an automatic analysis, etc. For this reason, there is a large time delay after measurement until the diagnosis result is obtained, and the prior arts are insufficient in prognosticating changes in a symptom or imminent danger. Furthermore, since the prior arts involve judgements through looking electrocardiogram by the naked eye of the doctor, there is a problem that oversight is likely to occur.